For building cross-platform 3D geospatial apps in Java
...With its flexible API and plugin system, WorldWind Java is a powerful platform for building interactive geospatial applications that need accurate globe rendering and data integration.
Crystal Space is an Open Source 3D SDK for Unix, Windows, and MacOS/X. It renders with OpenGL and features GLSL shaders, CG shaders, deferred rendering, dynamic shadows, bullet based physics library, terrain engine, skeleton based animation meshes, exporter for Blender, portals, etc...
ODE for Java is a binding between C dynamics library ODE (Open Dynamics Engine, http://ode.org) and Java. Separate packages provide among other things a Java3D integration and thus a scenegraph representation of selected ODE objects.